Electronic scale and method for controlling electronic scale

ABSTRACT

A method for controlling an electronic scale in disclosed in this disclosure, which is applied to measure and indicate a state of an external force, comprises the following steps. A weight sensor detects the external force, and a controller drives a prompting device to emit a first light with a first optical characteristic when the external force detected by the weight sensor reaches a first weight. The controller drives the prompting device to emit a second light with a second optical characteristic when the prompting device emits the first light for a predetermined period, wherein the prompting device continuously emits the second light until the external force reaches a second weight.

CROSS-REFERENCE TO RELATED APPLICATIONS

This non-provisional application claims priority under 35 U.S.C. § 120on patent application Ser. No. 16/197,677 filed in U.S.A. on Nov. 21,2018, which claims priority under 35 U.S.C. § 119(a) on PatentApplication No(s). 107129259 filed in Taiwan, R.O.C. on Aug. 22, 2018,and the entire contents of which are hereby incorporated by reference.

TECHNICAL FIELD

The disclosure relates to an electronic scale, more particularly to amethod for controlling the electronic scale to help a user to learn thepreferable way to prepare beverage or drink.

BACKGROUND

Regarding the factors effecting the taste of a cup of coffee, inaddition to the coffee beans, the percentage of the coffee to water, thebrewing time, as well as the way and the timing to mix coffee powderswith the added water, is also important. For the purpose of learningwhether the water volume added into the coffee pot and the process areappropriate, there's provided with an electronic scale capable ofcommunicating with the relative mobile application of a user's mobilephone/tablet PC for teaching how to brew the coffee. When using saidelectronic scale, one should place the coffee pot on the electronicscale firstly, then the electronic scale detects the variance of theweight when the water is continuously added in to the coffee pot, whilethe electronic scale shows the variance of the weight in the formationof words, figures, diagrams or tables on the mobile application Theabove information may help the user to learn the preferable way to brewcoffee.

However, the user won't be able to know the information from theelectronic scale if the mobile application or the mobile phone/tablet PCis not present. Furthermore, when it is needed to brew a plurality ofcups of coffee in a short time period, the above said method of displayinformation on mobile application won't help the user to quickly andconcurrently brew a plurality of cups of coffee through a standardprocess.

For the above reasons, there is a need for an electronic scale and therelative control method presently to overcome the above problems.

SUMMARY

An electronic scale and the relative control method is disclosed in thisdisclosure, which are able to display the figures of the detected weightvariance as the particular light color or flashing frequency forindicating the user.

In an embodiment of this disclosure, the method for controlling anelectronic scale based on this disclosure, which is applied to measureand indicate an external force, comprises the following steps: A weightsensor detects the external force, and a controller drives a promptingdevice to emit a first light with a first optical characteristic whenthe external force detected by the weight sensor reaches a first weight.Additionally, the controller drives the prompting device to emit asecond light with a second optical characteristic when the promptingdevice emits the first light for a predetermined period, wherein theprompting device continuously emits the second light until the externalforce reaches a second weight.

In another embodiment of this disclosure, the method for controlling theelectronic scale based on this disclosure, which is applied to measureand indicate the external force, comprises the following steps: Theweight sensor performs a zeroing process, and the controller drives theprompting device to emit the first light when the weight sensor performsthe zeroing process. Moreover, the weight sensor detects the externalforce, and the controller drives the prompting device to emit the secondlight when the weight sensor detects the external force more than zeroand less than the first weight. In addition, the controller drives theprompting device to emit a third light when the external force detectedby the weight sensor reaches the first weight. Finally, the controllerdrives the prompting device to emit a fourth light when the promptingdevice emits the third light for the predetermined period, wherein theprompting device continuously emits the fourth light until the externalforce reaches the second weight.

In an embodiment of this disclosure, the electronic scale based on thisdisclosure comprises the following features: A shell is with a loadingsurface, and a weighting sensor is disposed in the shell, wherein theweighting sensor generates a weight signal according to the externalforce detected by the loading surface. Also, the electronic scalecomprises a controller disposed in the shell, and the controllerelectrically connects to the loading surface for receiving the weightsignal. Moreover, the electronic scale comprises a prompting devicedisposed at the shell, and the prompting device electrically connects tothe controller. Furthermore, the prompting device comprises at least onelight-emitting element disposed on the shell, and the controller drivesthe at least one light-emitting element of the prompting device togenerate the light respectively with different optical characteristicsaccording to a variance of the external force detected by the weightsensor.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will become more fully understood from thedetailed description given herein below and the accompanying drawingswhich are given by way of illustration only and thus are not limitativeof the present disclosure and wherein:

FIG. 1 is the stereogram of the electronic scale in an embodiment basedon this disclosure.

FIG. 2 is the structure diagram of the electronic scale in an embodimentbased on this disclosure.

FIG. 3 is the state diagram in use of the electronic scale in anembodiment based on this disclosure.

FIG. 4 is the flowchart of the method for controlling the electronicscale in an embodiment based on this disclosure.

FIG. 5 is the graph related to the time and the weight of the water.

FIG. 6 to FIG. 8 are the schematic diagram of the prompting device forprompting the user in another embodiment based on this disclosure.

DETAILED DESCRIPTION

In the following detailed description, for purposes of explanation,numerous specific details are set forth in order to provide a thoroughunderstanding of the disclosed embodiments. It will be apparent,however, that one or more embodiments may be practiced without thesespecific details. In other instances, well-known structures and devicesare schematically shown in order to simplify the drawing.

The electronic scale disclosed in the embodiments in this disclosure hasno limitation on the kind of the detected objects, and also has nolimitation on the brewing procedure for any kind of the drinks. However,the following embodiments are based on the brewing coffee procedure forthe specific exemplary illustration, while the detected objects detectedby the electronic scale comprises a coffee dripper, filter paper, coffeegrounds and a coffee pot.

Please refer to FIG. 1 to FIG. 3. FIG. 1 is the stereogram of theelectronic scale in an embodiment based on this disclosure, FIG. 2 isthe structure diagram of the electronic scale in an embodiment based onthis disclosure, and FIG. 3 is the state diagram in use of theelectronic scale in an embodiment based on this disclosure. Theelectronic scale 1 in this embodiment comprises a shell 10, a weightsensor 11, a controller 12, a prompting device 13, a communicationdevice 14, a control bottom 15 and a power source 16. Additionally, theweight sensor 11, the controller 12, the communication device 14 and thepower source 16 may be disposed on a circuit board 17, and each of theabove elements electrically connects to each other directly orindirectly. Also, the prompting device 13 and the control bottom 15 mayto be disposed on the shell 10 and electrically connect to the circuitboard 17.

Specifically, the shell 10 forms a space for receiving the circuit board17 as well as the above electronic elements, and the prompting device 13and the control bottom 15 are disposed at or on the shell 10. The shell10 comprises a loading surface 111, and the loading surface 111 faces tothe upside of the electronic scale 1 for loading the detected objectswhen the electronic scale 1 is in use. As the above descriptions, forthe example of brewing coffee, the detected objects include the coffeedripper 30, the filter paper, the coffee grounds and the coffee pot 20.

The weight sensor 11 is under the loading surface 111 in thisembodiment, and the weighting sensor 11 generates a weight signalaccording to the external force (such as the weight of the detectedobjects) detected by the loading surface 111. The controller 12electrically connects to the weight sensor 11, and the controller 12generates a control signal after the weight sensor 11 receives theweight signal. Also, the prompting device 13 electrically connects tothe controller 12, and the prompting device 13 generates the relatedprompting command according to the control signal. Particularly, theprompting device 13 comprises a plurality of light-emitting elements131, noticed that the prompting device 13 may comprise onelight-emitting element 131, alternatively. In addition, thelight-emitting elements 131 may be the monochromatic light-emittingdiodes (monochromatic LEDs), the multicolor light-emitting diodes(multicolor LEDs) or the optical fibers, and this embodiment is based onthe example of multicolor LEDs for illustrating. The prompting device 13is preferable to be disposed around the loading surface 111 or theperiphery of the shell 10, wherein said above light-emitting elements131 are preferable to be disposed between the intervals along a closedroute on the shell 10, and the closed route may be designed as a ring ora polygon. As FIG. 1 shows, said above light-emitting elements 131 aredisposed around the surface of the shell 10 in this embodiment. However,as the loading surface 111 is only a part of the top surface of theshell 10, these light-emitting elements 131 is also able to be disposedalong the periphery of the top surface of the shell 10, wherein theperiphery is parallel or coplanar to the loading surface 111.Furthermore, it may be a light transmitting layer 132 covering thelight-emitting element 131 for protecting the light-emitting element131, and the light from the light-emitting element 131 may be softthrough the transmitting layer 132. Said above light-emitting elements131 are not necessary to be disposed along the said closed route, thelight-emitting elements 131 also may be disposed along a line segment(such as a curve) in other embodiment in this disclosure. As the abovestructures show, the prompting device 13 operates according to thecontrol signal sent from the controller 12 for driving a part of or allof the light-emitting elements 131 to emit the light with specificcolors and/or specific flashing frequencies.

The communication device 14 electrically connects to the controller 12,so the controller 12 is able to be communication connection to anexternal device to the electronic scale 1. For instance, thecommunication device 14 comprises a Bluetooth modulate. When the userenables the Bluetooth modulate of the mobile communication device forthe device to communicate with the communication device 14 by anapplication program, the electronic scale 1 is able to display theinformation (such as the variance of the weight detected by the weightsensor 11) in the formation of words, figures, numbers, graphs or tableson the mobile communication device by the application program. Also, thecontrol bottom 15 electrically connects to the controller 12 for turningon or turning off the electronic scale 1 or for setting the weight shownby the electronic scale 1 as zero when the control bottom 15 is actuated(for example, the user presses the control bottom 15). The power source16 supplies the power to the electronic elements of the electronic scale1, wherein the electronic elements must operate with the electricity,such as the weight sensor 11, the controller 12, the prompting device13, the communication device 14. Particularly, the power source 16 maybe a battery for supplying DC power, or a DC power receiving port forreceiving the external DC power. Also, the power source 16 may be anAC/DC transformer for receiving external AC power.

For illustrating the operating process of the electronic scale 1, pleaserefer to FIG. 4 and FIG. 5, wherein FIG. 4 is the flowchart of themethod for controlling the electronic scale in an embodiment based onthis disclosure, and FIG. 5 is the graph related to the time and theweight of the added water during the process of the method forcontrolling the electronic scale in this embodiment. For an easyunderstanding of the operation, the following example is based on thelight with different flashing frequencies for prompting. However, anykind of different physical states of the light, such as differentbrightness levels, may be applied for prompting. This disclosure has nolimitation for the prompting form.

As FIG. 4 and FIG. 5 show, for the step S101, the controller 12 drivesthe prompting device 13 to emit a first light in a first flashingfrequency when the electronic scale 1 performs the zeroing process.Specifically, the user is able to press the control bottom 15 forperforming the zeroing process after the user puts the detected objectson the loading surface 111 of the electronic scale 1. Hence, the netweight of the detected objects (the weight before adding water) isdeducted by the electronic scale 1, and then the electronic scale 1 isable to merely display the weight of the water added in the coffee pot20 by the user. Moreover, the following description defines the weightof the water added into the coffee pot 20 as the external force detectedby the weight sensor 11. Because the first light flashes in the abovefirst flashing frequency, the electronic scale 1 is able to obviouslyprompt the user that the electronic scale 1 is currently in the zeroingprocess. Additionally, the first light is white light in thisembodiment.

For the step S102, as the zeroing process is finished, the controller 12drives the prompting device 13 to emit the first light with a flashingfrequency of 0 Hz (namely, continuously emitting the first light) forprompting the user to add water.

For the step S103, the user adds the water continuously for the firstwater-adding process (as the time period between T1 to T2 shown in FIG.5), and the controller 12 drives the prompting device 13 to emit asecond light with the flashing frequency of 0 Hz when the external forcedetected by the weight sensor 11 is more than zero and less than a firstweight W1. In this embodiment, the second light is blue, and the abovefirst water-adding process is for the purpose of making the coffeegrounds be wet.

For the step S104, the controller 12 drives the prompting device 13 toemit a second light with a second flashing frequency when the externalforce detected by the weight sensor 11 almost reaches the first weightW1 (for example, the weight of the water is less than the first weightW1 for 5 grams, or the weight of the water reaches 95% of the firstweight W1, but this disclosure is not thus limited). This step promptsthe user to stop the first water-adding process. Moreover, the secondflashing frequency may equal to the first flashing frequency or be morethan or less than the first flashing frequency.

For the step S105, the controller 12 drives the prompting device 13 toemit a third light with a flashing frequency of 0 Hz when the externalforce detected by the weight sensor 11 reaches a first weight W1.Furthermore, the third light is red light in this embodiment, whereinthe third light is applied to prompt the user to stop adding water inorder to start proceeding the coffee bloom process (shown as time T2 totime T3 in FIG. 5).

For the step S106, when the prompting device 13 emits the third lightalmost for a bloom period (such as starting at time T2 and passing by atime period less than the total time period (T3−T2) for one second onlyor starting at time T2 and passing by 95% of the period (T3−T2), whereinthe above conditions are the examples for description, and thisdisclosure is not thus limited by any other conditions), the controller12 drives the prompting device 13 to emit the third light at the thirdflashing frequency for prompting the user that the bloom period will befinished soon. In this embodiment, the length of the bloom period isshown as the time period (T3−T2) in FIG. 5. Furthermore, the thirdflashing frequency may equal to the first frequency flashing frequency.However, the third flashing frequency may be more than or be less thanthe first frequency flashing frequency.

For the step S107, when the prompting device 13 emits the third lightalmost for the bloom period, the controller 12 drives the promptingdevice 13 to emit the fourth light with a flashing frequency of 0 Hz forprompting the user to start to add water again. In addition, the fourthlight is blue in this embodiment.

For the step S108, when the user performs the second water-addingprocess (shown as the period “time T3 to time T4” in FIG. 5) and addsthe water continuously, one of the following steps S109-S111 areperformed. Specifically, if the changing rate of the external forcedetected by the weight sensor 11 is in a weight changing rate range,that is, the user adds water at a proper speed, the process performs thestep S109. If the changing rate of the external force detected by theweight sensor 11 is higher than the weight changing rate range, it meansthat the user adds water too fast and the process performs the stepS110. Alternatively, if the changing rate of the external force detectedby the weight sensor 11 is lower than the weight changing rate range, itmeans that the user adds water too slow and the process performs thestep S111. In an embodiment, the weight changing rate range includes aupper limit of the weight changing rate and a lower limit of the weightchanging rate. For example, the weight changing rate range may be 5g/sec to 8 g/sec, if the changing rate of the external force equals to 5g/sec or 8 g/sec, both of the two above conditions are in the weightchanging rate range. Otherwise, if the changing rate of the externalforce is smaller than 5 g/sec, said changing rate is lower than theweight changing rate range; also, if the changing rate of the externalforce is larger than 8 g/sec, said changing rate is higher than theweight changing rate range. In another embodiment, the weight changingrate range doesn't include the upper limit of the weight changing rateand the lower limit of the weight changing rate. In other words, if thechanging rate of the external force equals to 5 g/sec, said changingrate is lower than the weight changing rate range, and the changing rateof the external force is higher than the weight changing rate range ifthe changing rate of the external force equals to 8 g/sec.

For the step S109, the controller 12 drives the prompting device 13 toemit the fourth light with a flashing frequency of 0 Hz for promptingthe user to keep the current speed of adding water. For the step S110,the controller 12 drives the prompting device 13 to emit the fourthlight at a fifth flashing frequency for prompting the user to add waterslower than the current speed. For the step S111, the controller 12drives the prompting device 13 to emit the fourth light at a sixthflashing frequency for prompting the user to add water faster than thecurrent speed. The sixth flashing frequency is smaller than the fifthflashing frequency in this embodiment, but the sixth flashing frequencymay be larger than the fifth flashing frequency in other embodiment. Theprocess is preferable to perform the following step S112 after said stepS108, S110 or S111 is performed for a preset period (such as 1 second)and reflects whether the speed of adding water is in a proper range. Asa result, the user is able to precisely control the process of addingwater.

After the prompting device 13 prompts the information about thewater-adding speed to the user through the above step S109, S110 orS111), the process performs the step S112: the controller 12 determineswhether the external force detected by the weight sensor 11 reaches asecond weight W2 according to the weight signal sent from the weightsensor 11. If said external force detected by the weight sensor 11 doesnot reach the second weight W2, the process performs the above step S108for determining the relation between the changing rate of the externalforce and the weight changing rate range again. Alternatively, if saidexternal force detected by the weight sensor 11 reaches the secondweight W2, the process performs the following step S113.

For the step S113, the controller 12 drives the prompting device 13 toemit the fifth light with a flashing frequency of 0 Hz for prompting theuser to stop adding water immediately since the coffee brewing procedureis finished. In addition, the fifth light is white in this embodiment.

In another embodiment based on this disclosure, the step S104 and thestep S106 of the proposed method for controlling the electronic scalemay be skipped. In other words, when the detected external force almostreaches the first weight W1 and the brewing procedure almost reaches thebloom period, the prompting device 13 does not prompt the user by thesecond light at the second flashing frequency and the third light at thethird flashing frequency. The method for controlling the electronicscale in yet another embodiment based on this disclosure, the firstlight, the second light, the third light, the fourth light and the fifthlight may be in the same color with different brightness levels. Forinstance, the first light, the second light, the third light, the fourthlight and the fifth light are green lights with brightness levels frombright to dark, or blue lights with brightness levels from bright todark. Alternatively, another embodiment of the method for controllingthe electronic scale different from the above two embodiments, the firstlight, the second light, the third light, the fourth light and the fifthlight may be in different colors. For instance, the first light, thesecond light, the third light, the fourth light and the fifth light arein the white, the red, the blue, the green and the purple. In short, thegroup of the first light, the second light, the third light, the fourthlight and the fifth light comprises at least one different opticalcharacteristic. Particularly, any two lights sequentially shown next toeach other comprise at least one difference in optical characteristic.Hence, by the different optical characteristics, the user is able tovisually distinct that the brewing procedure is changing.

Please refer to FIG. 6 to FIG. 8. FIG. 6 to FIG. 8 are the schematicdiagrams of the prompting device of the electronic scale for promptingthe user in another embodiment based on this disclosure. As performingthe first water-adding process or the second water-adding process in thebrewing procedure, the user holds the kettle for adding water around theinterior face of the coffee dripper 30. Usually, the moving speed of thekettle around the coffee dripper 30 affects the quality of the coffee.Thus, in this embodiment, the controller 12 drives the light-emittingelements 131 of the prompting device 13 to emit the light sequentiallywith a switching frequency, while the prompting device 13 prompts theuser to move the kettle for adding water at a proper position related tothe lightened one(s) of the light-emitting elements 131. For example, inthe step S103, it may enable only one or few of said light-emittingelements 131 to emit the second light. Hence, the user is able toobserve that whether the dropped point of the adding water is close tothe one(s) of the light-emitting elements 131, which emits the secondlight. For the same reason, for the step S109 to the step S111, it mayto enable only one or few of said light-emitting elements 131 to emitthe fourth light. Thus, the user is able to observe that whether thedropped point of the adding water is close to the light-emittingelements 131 which emits the fourth light. However, the prompting methodmay also work in a reverse way. For example, it may enable most of thelight-emitting elements 131, and the user is prompted by one or few ofthe unlit light-emitting elements 131, which are disabled and indicatethe proper position.

Through the electronic scale and the control method thereof disclosed inthis disclosure, according to the default setting or the user setting,the controller sends the control signal so as to drive a part of or allof the light-emitting elements to emit the light with the specific coloror the specific flashing frequency. Hence, without the applicationprogram or the mobile phone for displaying the information, theelectronic scale is still able to prompt the user to finish the coffeebrewing procedure properly. Furthermore, when the light-emittingelements 131 disposed along the above route on the prompting device 13are lightened in order, this process further helps the user to controlthe moving path of the dropped position of the adding water. As aresult, the quality of the brewed coffee is improved by this method.

The embodiments depicted above and the appended drawings are exemplaryand are not intended to be exhaustive or to limit the scope of thepresent disclosure to the precise forms disclosed. Many modificationsand variations are possible in view of the above teachings.

What is claimed is:
 1. A method for controlling an electronic scale tomeasure and indicate an external force, the method comprising: detectingthe external force increased by a weight sensor; driving a promptingdevice to emit a first color light with a first flashing frequency by acontroller when a changing rate of the external force detected by theweight sensor is in a weight changing rate range; driving the promptingdevice to emit the first color light with a second flashing frequency bythe controller when the changing rate of the external force detected bythe weight sensor is higher than the weight changing rate range; anddriving the prompting device to emit the first color light with a thirdflashing frequency by the controller when the changing rate of theexternal force detected by the weight sensor is lower than the weightchanging rate range, wherein the first, second, and third flashingfrequencies are different flashing frequencies.
 2. The method forcontrolling an electronic scale according to claim 1, wherein the secondflashing frequency is less than the third flashing frequency.
 3. Themethod for controlling an electronic scale according to claim 1, whereinthe prompting device comprises a plurality of light-emitting elementsarranged in a route, and wherein the flashing frequency is to drive apart or all of the light-emitting elements to sequentially emit thefirst color light with a switching frequency.
 4. The method forcontrolling an electronic scale according to claim 1, wherein the methodfurther comprises: determining whether the external force detected bythe weight sensor reaches a first weight; in response to determinationthat the external force detected by the weight sensor reaches the firstweight, driving the prompting device to emit a second color light by thecontroller; and when the prompting device emitting the second colorlight for a predetermined period, driving the prompting device to emitthe first color light by the controller.
 5. The method for controllingan electronic scale according to claim 4, wherein the method furthercomprises: driving the prompting device emitting a third color lightwhen the external force detected by the weight sensor is more than zeroand less than the first weight.
 6. The method for controlling anelectronic scale according to claim 5, wherein the method furthercomprises: before driving the prompting device emitting a third colorlight when the external force detected by the weight sensor is more thanzero and less than the first weight, performing a zeroing process forthe weight sensor; and driving the prompting device emitting a fourthcolor light by the controller when the weight sensor performs thezeroing process.
 7. The method for controlling an electronic scaleaccording to claim 1, wherein the method further comprises: driving theprompting device to emit the first color light until the external forcedetected reaches a second weight.
 8. The method for controlling anelectronic scale according to claim 6, wherein a color of any two of thefourth color light, the third color light, the second color light andthe first color light sequentially shown next to each other are indifferent colors.
 9. The method for controlling an electronic scaleaccording to claim 6, wherein a color of any two of the fourth colorlight, the third color light, the second color light and the first colorlight sequentially shown next to each other are in different brightnesslevels of the color.
 10. An electronic scale, comprising: a shell with aloading surface; a weighting sensor disposed in the shell, wherein theweighting sensor generates a weight signal according to an externalforce applied on the loading surface; a controller disposed in the shelland electrically connecting to the weighting sensor for receiving theweight signal; and a prompting device electrically connecting to thecontroller, wherein the controller determines a changing rate of theexternal force increased detected by the weight sensor relative to aweight changing rate range to drive the prompting device to emit a firstcolor light with different corresponding flashing frequency.
 11. Theelectronic scale according to claim 10, wherein the prompting devicecomprises a plurality of light-emitting elements arranged in a route,and the controller drives a part or all of the light-emitting elementsto sequentially emit the first color light with a switching frequency.12. The electronic scale according to claim 10, wherein the controllerexecutes a method comprising: detecting the external force increased bythe weight sensor; driving the prompting device to emit the first colorlight with a first flashing frequency when the changing rate of theexternal force detected by the weight sensor is in the weight changingrate range; driving the prompting device to emit the first color lightwith a second flashing frequency when a changing rate of the externalforce detected by the weight sensor is higher than the weight changingrate range; and driving the prompting device to emit the first colorlight with a third flashing frequency when the changing rate of theexternal force detected by the weight sensor is lower than the weightchanging rate range.
 13. The electronic scale according to claim 10,wherein the controller executes the method further comprises:determining whether the external force detected by the weight sensorreaches a first weight; in response to determination that the externalforce detected by the weight sensor reaches the first weight, drivingthe prompting device to emit a second color light; and when theprompting device emitting the second color light for a predeterminedperiod, driving the prompting device to emit the first color light. 14.The electronic scale according to claim 13, wherein the controllerexecutes the method further comprises: driving the prompting deviceemitting a third color light when the external force detected by theweight sensor is more than zero and less than the first weight.
 15. Theelectronic scale according to claim 14, wherein the controller executesthe method further comprises: before driving the prompting deviceemitting a third color light when the external force detected by theweight sensor is more than zero and less than the first weight,performing a zeroing process for the weight sensor; and driving theprompting device emitting a fourth color light when the weight sensorperforms the zeroing process.
 16. The electronic scale according toclaim 10, wherein the controller drives the prompting device to emit thefirst color light until the external force detected reaches a secondweight.
 17. The electronic scale according to claim 15, wherein a colorof any two of the fourth color light, the third color light, the secondcolor light and the first color light sequentially shown next to eachother are in different colors.
 18. The electronic scale according toclaim 15, wherein a color of any two of the fourth color light, thethird color light, the second color light and the first color lightsequentially shown next to each other are in different brightness levelsof the color.